mod rotctl;

use tokio::{
    self,
    io::{AsyncBufReadExt, AsyncWriteExt, BufStream},
    net::{TcpListener, TcpStream},
    sync::{self, mpsc, watch},
    time,
};

use rotctl::Command;

use std::io;

async fn process_socket(
    socket: TcpStream,
    cmd_tx: mpsc::Sender<Command>,
    mut pos_rx: watch::Receiver<(f32, f32)>,
) {
    let mut stream = BufStream::new(socket);

    let mut line = String::new();

    loop {
        if let Ok(n) = stream.read_line(&mut line).await {
            if n == 0 {
                return;
            }

            println!("> {}", line);

            match rotctl::parse_command(&line) {
                Ok(cmd) => match cmd {
                    Command::GetPos => {
                        let (az, el) = pos_rx.borrow().clone();

                        stream
                            .write_all(format!("{}\n{}\n", az, el).as_bytes())
                            .await
                            .unwrap();
                        stream.flush().await.unwrap();
                    }
                    Command::Exit => {
                        stream.write_all("RPRT 0\n".as_bytes()).await.unwrap();
                        stream.flush().await.unwrap();
                        return;
                    }
                    cmd => {
                        cmd_tx.send(cmd).await.unwrap();
                        stream.write_all("RPRT 0\n".as_bytes()).await.unwrap();
                        stream.flush().await.unwrap();
                    }
                },
                Err(msg) => {
                    stream.write_all(msg.as_bytes()).await.unwrap();
                    stream.flush().await.unwrap();
                }
            }

            line.clear();
        } else {
            return;
        }
    }
}

async fn control_rotor(mut rx_cmd: mpsc::Receiver<Command>, pos_tx: watch::Sender<(f32, f32)>) {
    let mut actual_az = 0.0;
    let mut actual_el = 0.0;

    let mut target_az = 0.0;
    let mut target_el = 0.0;

    loop {
        tokio::select! {
            Some(command) = rx_cmd.recv() => {
                match command {
                    Command::SetPos(az, el) => {
                        println!("Received set pos {} {}", az, el);
                        target_az = az;
                        target_el = el;
                    }
                    _ => {}
                }
            },
            _ = time::sleep(time::Duration::from_millis(100)) => {
                if target_az < actual_az {
                    actual_az -= 1.0;
                } else if  target_az > actual_az  {
                    actual_az += 1.0;
                }

                if target_el < actual_el {
                    actual_el -= 1.0;
                } else if  target_el > actual_el  {
                    actual_el += 1.0;
                }

                pos_tx.send((actual_az, actual_el)).unwrap();
            },
            else => return
        };
    }
}

#[tokio::main]
async fn main() -> io::Result<()> {
    let (cmd_tx, cmd_rx) = mpsc::channel::<Command>(16);

    let (pos_tx, pos_rx) = watch::channel::<(f32, f32)>((0.0, 0.0));

    tokio::spawn(async move {
        control_rotor(cmd_rx, pos_tx).await;
    });

    let listener = TcpListener::bind("127.0.0.1:8080").await?;

    loop {
        let (socket, _) = listener.accept().await?;

        let cmd_tx = cmd_tx.clone();
        let pos_rx = pos_rx.clone();
        tokio::spawn(async move {
            process_socket(socket, cmd_tx, pos_rx).await;
        });
    }
}